Process of casting with plastic materials



Patented Nov. H, 1924.

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To all whom it may concem:

Be it known that LLOYD G. CornMAN a citizen of the United States, residing at Flint, in the county of Genesee and State of Michigan, has invented certain new and useful Improvements in Processes of Casting with Plastic Materials, of which the following is a specification.

his discovery relates to the casting of plastic materials and has special reference to the building of a finishingsurface on an otherwise porous and coarse surface of a hardened plastic or concrete 'material. Various concrete preparations and cementitious compounds are now being used to manufacture articles of every dayuse andare being used for the linings of refrigerators and other containers A very common preparation which is now being used for the 1min of refrigerators and for casting other articles, is what is known as oxochloride cement. However, like all of these concrete preparations, the surface of the finished casting is rather rough and porous and it is necessary to either work this with a trowel or else to apply a finish- 1n coat such as enamel.

a co-pending application Serial ll'o.

622,771, filed March 5, 1923, I have described and claimed what I believe to be a new process for casting plastic materials with an easily fusible spacing element between the hardening casting and the mold. With oxo-chloride cement and similar astings which expand in hardenin I find it almost necessary to use some kind ment of this kind to secure the proper parting of the mold from the casting when the latter has hardened. I find the most usegunl element to achieve theseresults is paraf- The object of the present invention is to afiord a process by which a finishing coat for the castin canbecaused to adhere to the easily fuel le-"spacing' element and can also be roperly'united with the casting.

- Ihave ound if a mixture of alcohol and pliedinthe form of e. 'um

plaster of Paris, water In Water h .1 um, or alcohol'and powdered plaster of aria be spread on to the-parafiine lining and the alcohol allowed to eva orete, that it'is possible then to a'ppl a t coating of the finishing element. 5 may be apof water and and Portland cement, or any 0 1 or material which sets and becomes. hard. Preferably,

Application filed march 14., 19%. Serial No. 625,123.

the best method to proceed isto spray the coatin material .on first in a thin layer or film. This should be done carefully so as not to disturb the powdered gypsum or other element. When this has become dry and set, this is sufliciently hard so that further layers of the coating material may be spread on without a great deal of care and without disturbing the powder.

When the finishing coat has been allowed to dry and set on the para'fiine lininlg, then I introduce the plastic substance t at will form the main body of the casting. This is sometimes referred to as mud, but more properly it is a concrete or cementitious sub stance that has the capacity of being mixed with water to form a plastic substance and to dry into a hard stony substance. No particular mixture 'or character of ingredients is necessary. So far as my improved process is concerned, it may be used in coating almost any substance t at has the prop-- erties of being plastic and hardening in the way, I have named. However, a substance with which I have. experimented and havesecured good results, 1s a substance that is now known to the trade as oxo-chloride? cement. v

The plastic material is introduced into the mold under great ressure, some 900 lbs. to the square inch. his forces the plastic material very closely together and compacts it and gives it greater tensile stren th than is ordinarily present in stone castings. Furthermore, it drives the main body of the casting and the finishing coat, closely together so that the finishing coat netrates nto the pores of the main bod o the castgreat many equivalents and at the same time, exclude a great .many materials which would not 'be practical edients. For instance,.in some of the c aims I havelused 1 the term mixture of alcohol and gypsum to describe the'initial coating or film which when thepnepel'ty of adhering to.

thepa element. a in some ofthe ale "E vs reierreid' to the material out of which the parting element is made as parafiine. In other claims I have referred to the coating material as a mixture of plaster of Paris. Now it will be obvious, that quite a few equivalents for these ingredients can be found in the way of substances hav- 7 ing substantially the same properties of the ingredients mentioned for the purpose 1n-- tended. Hence in those claims where it has the suitable pro erties to be enlisted and intending the claim to cover equivalent substances, many of which I have already named in the specification.

- In the claims I have spoken of applying the several films by spraymg. Obviously, it might be possible to get measurably good results by other ways of applying the films, hence I want it understood that other equivalent ways are not excluded by reason of the wording of the claims! It will be understood that by providing a suitable Wooden core or core of similar material in the mold, that both the casting or the coating for the casting may form on the wooden core more'in' the torm of a covering for a solid body, for instance, it is possible to cover an entire refrigerator door with a stone encasing by floating the door or the door frame in the mold as a core. Hence, I wish it understood that the process covers 7 either the making of solid castings or the molding of a stone covering on another element.

'VVhat I claim is:

1. The process of casting plastic materials with a finishing coat, which comprises the linlng of the mold with a parting material, the spraying of a wet film of material upon the parting element, said film having the property 0 adhering to the parting element when dry, the spraying of a second film of a coating material on said first film and allowing the same to set, then introducing a plastic cementitious or concrete material and allowing the whole casting to set and finally removing the mold.

2. The process of casting plastic 'materials with a finishin coat, which comprises the lining of the mo d with a parting material, the spraying of a wet film of material upon the parting element, said film having the proglerty of adhering to the parting element w en dry, the spraying of a second film of a coatingmaterial on said first film and allowing the same to set, then introducing a plastic cementitious or concrete materlal under relatively great pressure, and allowing the whole casting to set and finally removing the mold.

3. Ihe process of casting plastic materials with a finishing coat, which comprises the lining of the mold with parafiine, the spraying upon the parafiine of a liquid holding an ingredient in suspension and having the property of permitting the liquid to evaporate and leaving the suspended element adhering to the parafiine, then the spraying of a coating material upon the first named element and permitting the same to dry and set, then introducing a cementitious or concrete mixture in plastic condition and permitting the same to set, and finally removing the mold.

4. lhe process of casting lastic materials with a finishing coat, Wl110l'1 comprises the lining of the mold with a parting film,

the spraying upon said film of a mixture of alcohol and gypsum and permitting the same to dry, t en the spraying upon the same of a finishing coat and allowing the same to dry and harden, then the forcing of a plastic material into the mold and allowing the same to dry and set, and finally removing the mold from the casting.

5. The process of casting material with a finishing coat, which comprises the lining of the mold with parafline, the spraying of a mixture of alcohol and gypsum upon the parafiin'e and allowing the alcohol to evaporate, then the spraying of a film of a finishing material on the dry gypsum and per mitting the same to set, finally the introduction of a plastic material into the mold and allowing the same to set, and finally removing the mold from the casting.

6. A process of casting material with a finishing coat, which comprises the lining of a mold with parafiine, the spraying of a mixture of alcohol and gypsum upon the paraffine and permitting the alcohol to evaporate, the spraying of a film of finishing material on the same and permitting thesame to dry and set, again spraying a coat of finishin material on the first coat of hardened nishing material and allowing the same to set, then introducing a plastic material into the mold and permitting the same to dry and set, and finally removing the mold from the casting.

7. The process of casting plastic materials with a finishing coat, whlch comprises the lining of the mold with parafiine, the spraying of a film of alcohol and gypsum on theparafine and permitting the alcohol to evaporate, then the s raying of a mixture of plaster of Paris an liquid on the first mentioned film and allowing the same to set, then the introduction of a plastic material into the mold and allowing the same to set, and finally removing the mold from the casting.

8. The process of casting plastic materials with a, finishing coat, which comprises the lining of the mold with parae, the spray ice lltl

Bill

v on the para" mixture of fine cementltious material on to- V ing of a mixture of alcohol and gypsum on to the paraffine permitting the alcohol to dry and the psum to remain as a powder e, the spraying of a, liquid the dry gypsum and permitting the same to set, the introduction of a concrete or cem- LLOYD G. .CGPEMAN. Y 

